'poorly-documented' originates from English, specifically the compound of 'poorly' and 'documented,' where 'poorly' meant 'in an inadequate manner' and 'documented' meant 'recorded or supported by documents.'

'documentum' transformed into the French word 'document,' and eventually became the modern English word 'document'; the English verb 'document' then formed the past participle 'documented.' In parallel, Old French 'povre' became Middle English 'poure/poore' and eventually the modern English 'poor,' from which the adverb 'poorly' developed with the suffix '-ly.' These elements combined in Modern English as the hyphenated compound 'poorly-documented.'

Initially, it meant 'documented in a poor or inadequate way,' and over time it came to broadly denote being insufficiently recorded or supported by documentation across contexts such as software, history, and research.